β-diketiminate ligand sources and metal-containing compounds thereof, and systems and methods including same

ABSTRACT

The present invention provides metal-containing compounds that include at least one β-diketiminate ligand, and methods of making and using the same. In certain embodiments, the metal-containing compounds include at least one β-diketiminate ligand with at least one fluorine-containing organic group as substituent. In other certain embodiments, the metal-containing compounds include at least one β-diketiminate ligand with at least one aliphatic group as a substituent selected to have greater degrees of freedom than the corresponding substituent in the β-diketiminate ligands of certain metal-containing compounds known in the art. The compounds can be used to deposit metal-containing layers using vapor deposition methods. Vapor deposition systems including the compounds are also provided. Sources for β-diketiminate ligands are also provided.

This is a divisional of application Ser. No. 11/169,065, filed Jun. 28,2005, now U.S. Pat. No. 7,439,338, which is incorporated herein byreference.

BACKGROUND

The scaling down of integrated circuit devices has created a need toincorporate high dielectric constant materials into capacitors andgates. The search for new high dielectric constant materials andprocesses is becoming more important as the minimum size for currenttechnology is practically constrained by the use of standard dielectricmaterials. Dielectric materials containing alkaline earth metals canprovide a significant advantage in capacitance compared to conventionaldielectric materials. For example, the perovskite material SrTiO₃ has adisclosed bulk dielectric constant of up to 500.

Unfortunately, the successful integration of alkaline earth metals intovapor deposition processes has proven to be difficult. For example,although atomic layer deposition (ALD) of alkaline earth metaldiketonates has been disclosed, these metal diketonates have lowvolatility, which typically requires that they be dissolved in organicsolvent for use in a liquid injection system. In addition to lowvolatility, these metal diketonates generally have poor reactivity,often requiring high substrate temperatures and strong oxidizers to growa film, which is often contaminated with carbon. Other alkaline earthmetal sources, such as those including substituted or unsubstitutedcyclopentadienyl ligands, typically have poor volatility as well as lowthermal stability, leading to undesirable pyrolysis on the substratesurface.

New sources and methods of incorporating high dielectric materials arebeing sought for new generations of integrated circuit devices.

SUMMARY OF THE INVENTION

The present invention provides metal-containing compounds (i.e.,metal-containing complexes) that include at least one β-diketiminateligand, and methods of making and using, and vapor deposition systemsincluding the same. Certain metal-containing compounds having at leastone β-diketiminate ligand are known in the art. In such certain knownmetal-containing compounds the β-diketiminate ligand has isopropylsubstituents on both nitrogen atoms, or tert-butyl substituents on bothnitrogen atoms. See, for example, El-Kaderi et al., Organometallics,23:4995-5002 (2004). The present invention provides metal-containingcompounds (i.e., metal-containing complexes) including at least oneβ-diketiminate ligand, which can have desirable properties (e.g., one ormore of higher vapor pressure, lower melting point, and lowersublimation point) for use in vapor deposition methods.

In certain embodiments, the present invention provides metal-containingcompounds having at least one β-diketiminate ligand with at least onefluorine-containing organic group as a substituent. In other certainembodiments, the present invention provides metal containing compoundshaving at least one β-diketiminate ligand with at least one aliphaticgroup as a substituent selected to have greater degrees of freedom thanthe corresponding substituent in the β-diketiminate ligands of certainmetal-containing compounds known in the alt.

In one aspect, the present invention provides a method of forming ametal-containing layer on a substrate (e.g., a semiconductor substrateor substrate assembly) using a vapor deposition process. The method canbe useful in the manufacture of semiconductor structures. The methodincludes: providing a substrate; providing a vapor including at leastone compound of the formula (Formula I):

and contacting the vapor including the at least one compound of FormulaI with the substrate (and typically directing the vapor to thesubstrate) to form a metal-containing layer on at least one surface ofthe substrate. The compound of the formula (Formula I) includes at leastone β-diketiminate ligand, wherein M is selected from the groupconsisting of a Group 2 metal, a Group 3 metal, a Lanthanide, andcombinations thereof; each L is independently an anionic ligand; each Yis independently a neutral ligand; n represents the valence state of themetal; z is from 0 to 10; x is from 1 to n; and each R¹, R², R³, R⁴, andR⁵ is independently hydrogen or an organic group with the proviso thatat least one of the R groups is a fluorine-containing organic group.

In another aspect, the present invention provides a method of forming ametal-containing layer on a substrate (e.g., a semiconductor substrateor substrate assembly) using a vapor deposition process. The method canbe useful in the manufacture of semiconductor structures. The methodincludes: providing a substrate; providing a vapor including at leastone compound of the formula (Formula I):

and contacting the vapor including the at least one compound of FormulaI with the substrate (and typically directing the vapor to thesubstrate) to form a metal-containing layer on at least one surface ofthe substrate. The compound of the formula (Formula I) includes at leastone β-diketiminate ligand, wherein M is selected from the groupconsisting of a Group 2 metal, a Group 3 metal, a Lanthanide, andcombinations thereof; each L is independently an anionic ligand; each Yis independently a neutral ligand; n represents the valence state of themetal; z is from 0 to 10; x is from 1 to n; and each R¹, R², R³, R⁴ andR⁵ is independently hydrogen or an aliphatic group (preferably analiphatic moiety) having 1 to 5 carbon atoms, with the proviso that atleast one of R², R³, and R⁴ is a moiety selected from the groupconsisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl,n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl,isopentyl, tert-pentyl, and neopentyl.

In another aspect, the present invention provides a method of forming ametal-containing layer on a substrate (e.g., a semiconductor substrateor substrate assembly) using a vapor deposition process. The method canbe useful in the manufacture of semiconductor structures. The methodincludes: providing a substrate; providing a vapor including at leastone compound of the formula (Formula I):

and contacting the vapor including the at least one compound of FormulaI with the substrate (and typically directing the vapor to thesubstrate) to form a metal-containing layer on at least one surface ofthe substrate. The compound of the formula (Formula I) includes at leastone β-diketiminate ligand, wherein M is selected from the groupconsisting of a Group 2 metal, a Group 3 metal, a Lanthanide, andcombinations thereof; each L is independently an anionic ligand; each Yis independently a neutral ligand; n represents the valence state of themetal; z is from 0 to 10; x is from 1 to n; and each R¹, R², R³, R⁴, andR⁵ is independently hydrogen or an aliphatic group (preferably analiphatic moiety) having 1 to 5 carbon atoms, with the proviso that atleast one of R¹ and R⁵ is a moiety selected from the group consisting ofn-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl, 2-pentyl, 3-pentyl,2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, and tert-pentyl.

In another aspect, the present invention provides metal-containingcompounds having at least one β-diketiminate ligand, precursorcompositions including such compounds, vapor deposition systemsincluding such compounds, and methods of making such compounds. Suchmetal-containing compounds include those of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;and x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an organic group with the proviso that at least one of the Rgroups is a fluorine-containing organic group. The present inventionalso provides sources for β-diketiminate ligands having afluorine-containing aliphatic group, and methods of making same, whichare useful for making metal-containing compounds having at least oneβ-diketiminate ligand having a fluorine-containing organic group.

In another aspect, the present invention provides metal-containingcompounds having certain β-diketiminate ligands, precursor compositionsincluding such compounds, vapor deposition systems including suchcompounds, and methods of making such compounds. Such metal-containingcompounds include those of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or an aliphaticgroup (preferably an aliphatic moiety) having 1 to 5 carbon atoms, withthe proviso that at least one of R², R³, and R⁴ is a moiety selectedfrom the group consisting of ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, isobutyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl,3-methyl-2-butyl, isopentyl, tert-pentyl, and neopentyl.

In another aspect, the present invention provides metal-containingcompounds having certain β-diketiminate ligands, precursor compositionsincluding such compounds, vapor deposition systems including suchcompounds, and methods of making such compounds. Such metal-containingcompounds include those of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or an aliphaticgroup (preferably an aliphatic moiety) having 1 to 5 carbon atoms, withthe proviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl.

Advantageously, the metal-containing compounds of the present inventioncan have desirable properties (e.g., one or more of higher vaporpressure, lower melting point, and lower sublimation point) for use invapor deposition methods.

DEFINITIONS

As used herein, formulas of the type:

are used to represent pentadienyl-group type ligands (e.g.,β-diketiminate ligands) having delocalized electron density that arecoordinated to a metal. The ligands may be coordinated to the metalthrough one, two, three, four, and/or five atoms (i.e., η¹-, η²-, η³-,η⁴-, and/or η⁵-coordination modes).

As used herein, the term “organic group” is used for the purpose of thisinvention to mean a hydrocarbon group that is classified as an aliphaticgroup, cyclic group, or combination of aliphatic and cyclic groups(e.g., alkaryl and aralkyl groups). In the context of the presentinvention, suitable organic groups for metal-containing compounds ofthis invention are those that do not interfere with the formation of ametal oxide layer using vapor deposition techniques. In the context ofthe present invention, the term “aliphatic group” means a saturated orunsaturated linear or branched hydrocarbon group. This term is used toencompass alkyl, alkenyl, and alkynyl groups, for example. The term“alkyl group” means a saturated linear or branched monovalenthydrocarbon group including, for example, methyl, ethyl, n-propyl,isopropyl, tert-butyl, amyl, heptyl, and the like. The term “alkenylgroup” means an unsaturated, linear or branched monovalent hydrocarbongroup with one or more olefinically unsaturated groups (i.e.,carbon-carbon double bonds), such as a vinyl group. The term “alkynylgroup” means an unsaturated, linear or branched monovalent hydrocarbongroup with one or more carbon-carbon triple bonds. The term “cyclicgroup” means a closed ring hydrocarbon group that is classified as analicyclic group, aromatic group, or heterocyclic group. The term“alicyclic group” means a cyclic hydrocarbon group having propel-tiesresembling those of aliphatic groups. The term “aromatic group” or “arylgroup” means a mono- or polynuclear aromatic hydrocarbon group. The term“heterocyclic group” means a closed ring hydrocarbon in which one ormore of the atoms in the ring is an element other than carbon (e.g.,nitrogen, oxygen, sulfur, etc.).

As a means of simplifying the discussion and the recitation of certainterminology used throughout this application, the terms “group” and“moiety” are used to differentiate between chemical species that allowfor substitution or that may be substituted and those that do not soallow for substitution or may not be so substituted. Thus, when the term“group” is used to describe a chemical substituent, the describedchemical material includes the unsubstituted group and that group withnonperoxidic O, N, S, Si, or F atoms, for example, in the chain as wellas carbonyl groups or other conventional substituents. Where the term“moiety” is used to describe a chemical compound or substituent, only anunsubstituted chemical material is intended to be included. For example,the phrase “alkyl group” is intended to include not only pure open chainsaturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl,tert-butyl, and the like, but also alkyl substituents bearing furthersubstituents known in the art, such as hydroxy, alkoxy, alkylsulfonyl,halogen atoms, cyano, nitro, amino, carboxyl, etc. Thus, “alkyl group”includes ether groups, haloalkyls, nitroalkyls, carboxyalkyls,hydroxyalkyls, sulfoalkyls, etc. On the other hand, the phrase “alkylmoiety” is limited to the inclusion of only pure open chain saturatedhydrocarbon alkyl substituents, such as methyl, ethyl, propyl,tert-butyl, and the like.

As used herein, “metal-containing” is used to refer to a material,typically a compound or a layer, that may consist entirely of a metal,or may include other elements in addition to a metal. Typicalmetal-containing compounds include, but are not limited to, metals,metal-ligand complexes, metal salts, organometallic compounds, andcombinations thereof. Typical metal-containing layers include, but arenot limited to, metals, metal oxides, metal silicates, and combinationsthereof.

As used herein, “a,” “an,” “the,” and “at least one” are usedinterchangeably and mean one or more than one.

As used herein, the term “comprising,” which is synonymous with“including” or “containing,” is inclusive, open-ended, and does notexclude additional unrecited elements or method steps.

The terms “deposition process” and “vapor deposition process” as usedherein refer to a process in which a metal-containing layer is formed onone or more surfaces of a substrate (e.g., a doped polysilicon wafer)from vaporized precursor composition(s) including one or moremetal-containing compounds. Specifically, one or more metal-containingcompounds are vaporized and directed to and/or contacted with one ormore surfaces of a substrate (e.g., semiconductor substrate or substrateassembly) placed in a deposition chamber. Typically, the substrate isheated. These metal-containing compounds form (e.g., by reacting ordecomposing) a non-volatile, thin, uniform, metal-containing layer onthe surface(s) of the substrate. For the purposes of this invention, theterm “vapor deposition process” is meant to include both chemical vapordeposition processes (including pulsed chemical vapor depositionprocesses) and atomic layer deposition processes.

“Chemical vapor deposition” (CVD) as used herein refers to a vapordeposition process wherein the desired layer is deposited on thesubstrate from vaporized metal-containing compounds (and any reactiongases used) within a deposition chamber with no effort made to separatethe reaction components. In contrast to a “simple” CVD process thatinvolves the substantial simultaneous use of the precursor compositionsand any reaction gases, “pulsed” CVD alternately pulses these materialsinto the deposition chamber, but does not rigorously avoid intermixingof the precursor and reaction gas streams, as is typically done inatomic layer deposition or ALD (discussed in greater detail below).

The term “atomic layer deposition” (ALD) as used herein refers to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a processchamber (i.e., a deposition chamber). Typically, during each cycle theprecursor is chemisorbed to a deposition surface (e.g., a substrateassembly surface or a previously deposited underlying surface such asmaterial from a previous ALD cycle), forming a monolayer orsub-monolayer that does not readily react with additional precursor(i.e., a self-limiting reaction). Thereafter, if necessary, a reactant(e.g., another precursor or reaction gas) may subsequently be introducedinto the process chamber for use in converting the chemisorbed precursorto the desired material on the deposition surface. Typically, thisreactant is capable of further reaction with the precursor. Further,purging steps may also be utilized during each cycle to remove excessprecursor from the process chamber and/or remove excess reactant and/orreaction byproducts from the process chamber after conversion of thechemisorbed precursor. Further, the term “atomic layer deposition,” asused herein, is also meant to include processes designated by relatedterms such as, “chemical vapor atomic layer deposition”, “atomic layerepitaxy” (ALE) (see U.S. Pat. No. 5,256,244 to Ackerman), molecular beamepitaxy (MBE), gas source MBE, or organometallic MBE, and chemical beamepitaxy when performed with alternating pulses of precursorcomposition(s), reactive gas, and purge (e.g. inert carrier) gas.

As compared to the one cycle chemical vapor deposition (CVD) process,the longer duration multi-cycle ALD process allows for improved controlof layer thickness and composition by self-limiting layer growth, andminimizing detrimental gas phase reactions by separation of the reactioncomponents. The self-limiting nature of ALD provides a method ofdepositing a film on a wide variety of reactive surfaces, includingsurfaces with irregular topographies, with better step coverage than isavailable with CVD or other “line of sight” deposition methods such asevaporation or physical vapor deposition (PVD or sputtering).

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a vapor deposition system suitable foruse in methods of the present invention.

FIG. 2 is a graphical representation of degrees of freedom (x-axis) vs.melting point (° C.; y-axis) for various metal-containing compoundshaving at least one β-diketiminate ligand, which illustrates decreasingmelting point for increasing degrees of freedom. Degrees of freedom werequantified by a method described by Li et al. in Inorganic Chemistry,44:1728-1735 (2005), and as further described herein. SDtBK represents ametal-containing compound of Formula I having zero degrees of freedom,wherein M=Sr (n=2), R¹═R⁵=tert-butyl, R²═R⁴=methyl, R³═H, x=2, and z=0,SDiPtBK represents a metal-containing compound of Formula I having 2degrees of freedom (2 isopropyls), wherein M=Sr (n=2), R¹=isopropyl (1degree of freedom), R⁵=tert-butyl, R²═R⁴=methyl, R³═H, x=2, and z=0,SDiPK represents a metal-containing compound of Formula I having 4degrees of freedom (4 isopropyls), wherein M=Sr (n=2), R¹═R⁵=isopropyl(each isopropyl having 1 degree of freedom), R²═R⁴=methyl, R³═H, x=2,and z=0, SDsBK represents a metal-containing compound of Formula Ihaving 12 degrees of freedom (4 sec-butyls), wherein M=Sr (n=2),R¹═R⁵=sec-butyl (each sec-butyl having 3 degrees of freedom),R²═R⁴=methyl, R³═H, x=2, and z=0. The melting point for SDsBK (44-48°C.) is disclosed herein in Example 2. The melting points for SDtBK(127-129° C.) and SDiPK (87-89° C.) have been disclosed in El-Kaderi etal., Organometallics, 23:4995-5002 (2004). The melting point for SDiPtBK(see, U.S. Patent Application Publication No. 2008/0214001 A9 (Millwardet al.)) was measured as 109.5° C.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Certain metal-containing compounds having at least one β-diketiminateligand are known in the art. In such certain known metal-containingcompounds, the β-diketiminate ligand has isopropyl substituents on bothnitrogen atoms, or tert-butyl substituents on both nitrogen atoms. See,for example, El-Kaderi et al., Organometallics, 23:4995-5002 (2004). Thepresent invention provides metal-containing compounds (i.e.,metal-containing complexes) including at least one β-diketiminateligand, which can have desirable properties (e.g. one or more of highervapor pressure, lower melting point, and lower sublimation point) foruse in vapor deposition methods. The present invention also providesmethods of making and using such metal-containing compounds, and vapordeposition systems including the same.

In one aspect, the present invention provides metal-containing compoundshaving at least one β-diketiminate ligand with at least onefluorine-containing organic group as a substituent. Suchmetal-containing compounds including at least one fluorine-containingorganic group can provide higher volatility than correspondingmetal-containing compounds without a fluorine-containing organic group.Metal-containing compounds having higher volatility can be advantageousin deposition methods (e.g., CVD and ALD).

In another aspect, the present invention provides metal containingcompounds having at least one β-diketiminate ligand with at least onealiphatic group (preferably an aliphatic moiety) having 1 to 5 carbonatoms as a substituent, wherein the aliphatic group is selected to havegreater degrees of freedom than the corresponding substituent in theβ-diketiminate ligands of certain metal-containing compounds known inthe art (i.e., compounds of Formula I wherein R²═R⁴=methyl; R³═H; andR¹═R⁵=isopropyl or R¹═R⁵=tert-butyl). Such metal-containing compoundshaving at least one β-diketiminate ligand with at least one substituenthaving greater degrees of freedom than the corresponding substituent incertain known metal-containing compounds can have lower melting pointsand/or sublimation points than the certain known metal-containingcompounds. Metal-containing compounds having lower melting points, lowersublimation points, or both, can be advantageous in deposition methods(e.g., CVD and ALD). For example, metal-containing compounds havinglower melting points are particularly useful for molten precursorcompositions, because the vapor pressure of molten materials istypically higher than that of analogous solid materials at the sametemperature. In addition, the surface area of vaporizing moltenprecursor compositions (and thus the rates of vaporization from and heattransfer to such compositions) can change at regular and predictablerates. Finally, molten precursor compositions are typically not a sourcefor undesirable particles in the deposition process. Thus, for a givenclass of precursor compositions, molten forms within that class canprovide adequate vapor pressure for deposition at lower temperaturesthan non-molten forms, under reproducible conditions, and preferablywithout producing problematic particles in the process.

In some embodiments, the metal-containing compounds are homolepticcomplexes (i.e., complexes in which the metal is bound to only one typeof ligand) that include β-diketiminate ligands, which can be symmetricor unsymmetric. In other embodiments, the metal-containing compounds areheteroleptic complexes (i.e., complexes in which the metal is bound tomore than one type of ligand) including at least one β-diketiminateligand, which can be symmetric or unsymmetric. See, for example,emending U.S. Patent Application Publication No. 2008/0214001 A9(Millward et al.). In some embodiments, the β-diketiminate ligand can bein the η⁵-coordination mode.

Compounds with at Least One Fluorine-Containing Organic Group

In one aspect, metal-containing compounds including at least onediketiminate ligand having at least one fluorine-containing organicgroup, and precursor compositions including such compounds, aredisclosed. Such metal-containing compounds including at least onefluorine-containing organic group can provide higher volatility thancorresponding metal-containing compounds without a fluorine-containingorganic group. Metal-containing compounds having higher volatility canbe advantageous in deposition methods (e.g., CVD and ALD).

Such compounds include a compound of the formula (Formula I):

wherein M is a Group 2 metal (e.g., Ca, Sr, Ba), a Group 3 metal (e.g.,Sc, Y, La), a Lanthanide (e.g., Pr, Nd), or a combination thereof.Preferably M is Ca, Sr, or Ba. More preferably M is Sr. Each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;and x is from 1 to n.

Each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or an organicgroup (e.g., an alkyl group or, in certain embodiments all alkylmoiety), with the proviso that at least one R group is afluorine-containing organic group. In certain embodiments, R¹, R², R³,R⁴, and R⁵ are each independently hydrogen or an organic group having 1to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, butyl,sec-butyl, tert-butyl), and preferably hydrogen or an aliphatic grouphaving 1 to 5 carbon atoms. In certain embodiments, R³═H and at leastone of R¹, R², R⁴, and R⁵ is a fluorine-containing organic group.

The fluorine-containing organic group may be a partially fluorinatedgroup (i.e., some, but not all, of the hydrogens have been replaced byfluorine) or a fully fluorinated group (i.e., a perfluoro group in whichall of the hydrogens have been replaced by fluorine). In certainembodiments, the fluorine-containing organic group is afluorine-containing aliphatic group, and preferably afluorine-containing alkyl group. Exemplary fluorine-containing alkylgroups include, —CH₂F, —CHF₂, —CF₃, —CH₂CF₃, —CF₂CF₃, —CH₂CH₂CF₃,—CF₂CF₂CF₃, —CH(CH₃)(CF₃), —CH(CF₃)₂, —CF(CF₃)₂, —CH₂CH₂CH₂CF₃,—CF₂CF₂CF₂CF₃, —CH(CF₃)(CF₂CF₃), —CF(CF₃)(CF₂CF₃), —C(CF₃)₃, and thelike.

L can represent a wide variety of anionic ligands. Exemplary anionicligands (L) include halides, alkoxide groups, amide groups, mercaptidegroups, cyanide, alkyl groups, amidinate groups, guanidinate groups,isoureate groups, β-diketonate groups, β-iminoketonate groups,β-diketiminate groups, and combinations thereof. In certain embodiments,L is a β-diketiminate group having a structure that is the same as thatof the β-diketiminate ligand shown in Formula I. In other certainembodiments, L is a β-diketiminate group (e.g., symmetric orunsymmetric) having a structure that is different than that of theβ-diketiminate ligand shown in Formula I.

Y represents an optional neutral ligand. Exemplary neutral ligands (Y)include carbonyl (CO), nitrosyl (NO), ammonia (NH₃), amines (NR₃),nitrogen (N₂), phosphines (PR₃), ethers (ROR), alcohols (ROH), water(H₂O), tetrahydrofuran, and combinations thereof, wherein each Rindependently represents hydrogen or an organic group. The number ofoptional neutral ligands (Y) is represented by z, which is from 0 to 10,and preferably from 0 to 3. More preferably, Y is not present (i.e.,z=0).

In one embodiment, a metal-containing compound including at least oneβ-diketiminate ligand having at least one fluorine-containing organicgroup as a substituent can be made, for example, by a method thatincludes combining components including a β-diketiminate ligand sourcehaving at least one fluorine-containing organic group as a substituent,a metal source, optionally a source for a neutral ligand Y, and a sourcefor an anionic ligand L, which can be the same or different than theβ-diketiminate ligand source having at least one fluorine-containingorganic group as a substituent. Typically, a ligand source can bedeprotonated to become a ligand.

An exemplary method includes combining components including: a ligandsource of the formula (Formula III):

a tautomer thereof, or a deprotonated conjugate base or metal complexthereof (e.g., a tin complex); a source for an anionic ligand L (e.g. asdescribed herein); optionally a source for a neutral ligand Y (e.g. asdescribed herein); and a metal (M) source under conditions sufficient toform the metal-containing compound. Preferably, the components arecombined in an organic solvent (e.g., heptane, toluene, or diethylether), typically under mixing or stirring conditions, and allowed toreact at a convenient temperature (e.g. room temperature or below,refluxing or above, or an intermediate temperature) for a length of timeto form a sufficient amount of the desired product. Preferably, thecomponents are combined under an inert atmosphere (e.g., argon),typically in the substantial absence of water.

The metal (M) source can be selected from the group consisting of aGroup II metal source, a Group III metal source, a Lanthanide metalsource, and combinations thereof. A wide variety of suitable metalsources would be apparent to one of skill. Such metal sources canoptionally include at least one neutral ligand Y as defined hereinabove. Exemplary metal sources include, for example, a M(II) halide(i.e., a M(II) compound having at least one halide ligand), a M(II)pseudohalide (i.e., a M(II) compound having at least one pseudohalideligand), a M(II) amide (i.e., a M(II) compound having at least one amideligand, e.g., a M(II) bis(hexamethyldisilazane) and/or a M(II)bis(hexamethyldisilazane)-bis(tetrahydrofuran)), a M(0) for use in ametal exchange reaction with a β-diketiminate metal complex (e.g., a tincomplex), or combinations thereof.

Each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or an organicgroup (e.g., an alkyl group or, in certain embodiments, an alkylmoiety), with the proviso that at least one R group is afluorine-containing organic group. In certain embodiments, R³═H and atleast one of R¹, R², R⁴, and R⁵ is a fluorine-containing organic group.

The method provides a metal-containing compound of the formula (FormulaI):

wherein M, L, Y, R¹, R², R³, R⁴, and R⁵ are as defined above, nrepresents the valence state of the metal, z is from 0 to 10, and x isfrom 1 to n.

Sources for β-diketiminate ligands having at least onefluorine-containing aliphatic group as a substituent can be made, forexample, using condensation reactions. For example, exemplaryβ-diketiminate ligand sources having at least one fluorine-containingaliphatic group can be made by a method including combining an amine ofthe formula R¹NH₂ with a compound of the formula (Formula IV):

or a tautomer thereof,in the presence of an agent capable of activating the carbonyl group forreaction with the amine, under conditions sufficient to provide a ligandsource of the formula (Formula III):

or a tautomer thereof.Preferably, the components are combined in an organic solvent (e.g.,heptane, toluene, or diethyl ether), typically under mixing or stirringconditions, and allowed to react at a convenient temperature (e.g., roomtemperature or below, refluxing or above, or an intermediatetemperature) for a length of time to form a sufficient amount of thedesired product. Preferably, the components are combined under an inertatmosphere (e.g. argon), typically in the substantial absence of water.

Each R¹, R², R³, R⁴, and R⁵ is independently hydrogen or an aliphaticgroup (e.g., methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,tert-butyl), with the proviso that at least one of the R groups is afluorine-containing aliphatic group. In certain embodiments, R³═H and atleast one of R¹, R², R⁴, and R⁵ is a fluorine-containing aliphaticgroup. Accordingly, the present invention also provides ligand sourcesof Formula III.

Tautomers of compounds of Formula III and Formula IV include isomers inwhich a hydrogen atom is bonded to another atom. Typically, tautomerscan be in equilibrium with one another.

Specifically, the present invention contemplates tautomers of FormulaIII including, for example,

Similarly, the present invention contemplates tautomers of Formula IVincluding, for example,

Suitable activating agents capable of activating a carbonyl group forreaction with an amine are well known to those of skill in the art andinclude, for example, alkylating agents and Lewis acids (e.g., TiCl₄).Exemplary alkylating agents include triethyloxonium tetrafluoroborate,dimethyl sulfate, nitrosoureas, mustard gases (e.g.,1,1-thiobis(2-chloroethane)), and combinations thereof.

Additional metal-containing compounds including at least onediketiminate ligand halving at least one fluorine-containing organicgroup can be made, for example, by ligand exchange reactions between ametal-containing compound including at least one β-diketiminate ligandhaving at least one fluorine-containing organic group, and ametal-containing compound including at least one differentβ-diketiminate ligand. Such an exemplary method includes combiningcomponents including a compound of the formula (Formula I):

and a compound of the formula (Formula V):

under conditions sufficient to form the metal-containing compound.

Each M is a Group 2 metal, a Group 3 metal, a Lanthanide, or acombination thereof; each L is independently an anionic ligand; each Yis independently a neutral ligand; n represents the valence state of themetal; z is from 0 to 10; and x is from 1 to n.

Each R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ is independentlyhydrogen or an organic group, with the proviso that at least one R groupis a fluorine-containing organic group; and the β-diketiminate ligandsshown in Formula I and Formula V have different structures.

The method can provide a metal-containing compound of the formula(Formula II):

wherein M, L, Y, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, n, and z areas defined above.Compounds with at Least One Substituent Having Greater Degrees ofFreedom

In another aspect, the present invention provides metal containingcompounds having at least one β-diketiminate ligand with at least onealiphatic group (preferably an aliphatic moiety) having 1 to 5 carbonatoms as a substituent, wherein the aliphatic group is selected to havegreater degrees of freedom than the corresponding substituent in theβ-diketiminate ligands of certain metal-containing compounds known inthe art (i.e., compounds of Formula I wherein R²═R⁴=methyl; R³═H; andR¹═R⁵=isopropyl or R¹═R⁵=tert-butyl). See, for example, El-Kaderi etal., Organometallics, 23:4995-5002 (2004).

One scheme for quantifying degrees of freedom of a substituent of aligand of a metal-containing compound has been disclosed by Li et al. inInorganic Chemistry, 44:1728-1735 (2005). In this scheme for countingthe degrees of freedom, rotations about non-hydrogen single bonds(including the single bond attaching a substituent to a ligand) arecounted. However, a single bond that only rotates a methyl group aroundits 3-fold axis, or a single bond that only rotates a tert-butyl grouparound its 3-fold axis, are ignored, because the resulting changes inenergy might not have much influence on crystal packing. A chiral carbonatom (i.e., a carbon atom having four different substituents) counts asan additional degree of freedom, because enantiomers cannot interconvertat typical temperatures encountered in deposition methods. The abovescheme was used to quantify degrees of freedom for some exemplarysubstituents, and the results are given in Table 1.

TABLE 1 Total Degrees of Freedom Quantified for Exemplary SubstituentsC—C Bond Chiral Degrees of Substituent Rotations Carbons Freedom —H 0 00 —CH₃ (methyl) 0 0 0 —CH₂CH₃ (ethyl) 1 0 1 —CH₂CH₂CH₃ (n-propyl) 2 0 2—CH(CH₃)₂ (isopropyl) 1 0 1 —CH₂CH₂CH₂CH₃ (n-butyl) 3 0 3—CH(CH₃)(CH₂CH₃) (sec-butyl) 2 1 3 —CH₂CH(CH₃)₂ (isobutyl) 2 0 2—C(CH₃)₃ (tert-butyl) 0 0 0 —CH₂CH₂CH₂CH₂CH₃ (n-pentyl) 4 0 4—CH(CH₃)(CH₂CH₂CH₃) (2-pentyl) 3 1 4 —CH(CH₂CH₃)₂ (3-pentyl) 3 0 3—CH₂CH(CH₃)(CH₂CH₃) 3 1 4 (2-methyl-1-butyl) —CH(CH₃)(CH(CH₃)₂) 2 1 3(3-methyl-2-butyl) —CH₂CH₂CH(CH₃)₂ (isopentyl) 3 0 3 —C(CH₃)₂(CH₂CH₃)(tert-pentyl) 2 0 2 —CH₂C(CH₃)₃ (neopentyl) 1 0 1The above described method for quantifying degrees of freedom of asubstituent of a ligand of a metal-containing compound is one exemplaryapproach. One of skill in the art will appreciate that other methods forquantifying degrees of freedom of a substituent of a ligand of ametal-containing compound could also be used as desired.

Such metal-containing compounds having at least one β-diketiminateligand with at least one substituent having greater degrees of freedomthan the corresponding substituent in certain known metal-containingcompounds can have lower melting points and/or sublimation points thancertain known metal-containing compounds with at least oneβ-diketiminate ligand. Metal-containing compounds having lower meltingpoints, lower sublimation points, or both, can be advantageous indeposition methods (e.g., CVD and ALD). For example, metal-containingcompounds having lower melting points are particularly useful for moltenprecursor compositions, because the vapor pressure of molten materialsis typically higher than that of analogous solid materials at the sametemperature. In addition, the surface area of vaporizing moltenprecursor compositions (and thus the rates of vaporization from and heattransfer to such compositions) can change at regular and predictablerates. Finally, molten precursor compositions are typically not a sourcefor undesirable particles in the deposition process. Thus, for a givenclass of precursor compositions, molten forms within that class canprovide adequate vapor pressure for deposition at lower temperaturesthan non-molten forms, under reproducible conditions, and preferablywithout producing problematic particles in the process.

In one aspect, the present invention provides metal-containing compoundshaving at least one β-diketiminate ligand with at least one substituenthaving greater degrees of freedom than the corresponding substituent incertain known metal-containing compounds. Such compounds include acompound of the formula (Formula I):

wherein M is a Group 2 metal (e.g., Ca, Sr, Ba), a Group 3 metal (e.g.,Sc, Y, La), a Lanthanide (e.g., Pr, Nd), or a combination thereof.Preferably M is Ca, Sr, or Ba. More preferably, M is Sr. Each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;and x is from 1 to n.

In one embodiment, each R¹, R², R³, R⁴, and R⁵ is independently hydrogenor an aliphatic group (e.g., an alkyl group or, in certain embodiments,an alkyl moiety) having 1 to 5 carbon atoms, with the proviso that atleast one of R², R³, and R⁴ is a moiety selected from the groupconsisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl,n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl,isopentyl, tert-pentyl, and neopentyl. Notably the moieties listed inthe above group all have higher quantified degrees of freedom (e.g.,Table 1) than the corresponding substituents (R²═R⁴=methyl; and R³═H) inthe metal-containing compounds disclosed in El-Kaderi et al.,Organometallics, 23:4995-5002 (2004).

In another embodiment, each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group (e.g., an alkyl group or, in certainembodiments, an alkyl moiety) having 1 to 5 carbon atoms, with theproviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl. Notably the moieties listed in the above group all havehigher quantified degrees of freedom (e.g., Table 1) than thecorresponding substituents (R¹═R⁵=isopropyl; or R¹═R⁵=tert-butyl) in themetal-containing compounds disclosed in El-Kaderi et al.,Organometallics, 23:4995-5002 (2004).

L can represent a wide variety of anionic ligands. Exemplary anionicligands (L) include halides, alkoxide groups, amide groups, mercaptidegroups, cyanide, alkyl groups, amidinate groups, guanidinate groups,isoureate groups, β-diketonate groups, β-iminoketonate groups,β-diketiminate groups, and combinations thereof. In certain embodiments,L is a β-diketiminate group having a structure that is the same as thatof the β-diketiminate ligand shown in Formula I. In other certainembodiments, L is a β-diketiminate group (e.g., symmetric orunsymmetric) having a structure that is different than that of theβ-diketiminate ligand shown in Formula I.

Y represents an optional neutral ligand. Exemplary neutral ligands (Y)include carbonyl (CO), nitrosyl (NO), ammonia (NH₃), amines (NR₃),nitrogen (N₂), phosphines (PR₃), ethers (ROR), alcohols (ROH), water(H₂O), tetrahydrofuran, and combinations thereof, wherein each Rindependently represents hydrogen or an organic group. The number ofoptional neutral ligands (Y) is represented by z, which is from 0 to 10,and preferably from 0 to 3. More preferably, Y is not present (i.e.,z=0).

In one embodiment, a metal-containing compound including at least oneβ-diketiminate ligand with at least one substituent having greaterdegrees of freedom than the corresponding substituent in certain knownmetal-containing compounds can be made, for example, by a method thatincludes combining components including a β-diketiminate ligand sourcewith at least one substituent having greater degrees of freedom than thecorresponding substituent in certain known metal-containing compounds, ametal source, optionally a source for a neutral ligand Y, and a sourcefor an anionic ligand L, which can be the same or different than theβ-diketiminate ligand source with at least one substituent havinggreater degrees of freedom than the corresponding substituent in certainknown metal-containing compounds. Typically, a ligand source can bedeprotonated to become a ligand.

An exemplary method includes combining components including: a ligandsource of the formula (Formula III):

a tautomer thereof, or a deprotonated conjugate base or metal complexthereof; a source for an anionic ligand L (e.g., as described herein);optionally a source for a neutral ligand Y (e.g., as described herein);and a metal (M) source under conditions sufficient to form themetal-containing compound. Preferably, the components are combined in anorganic solvent (e.g., heptane, toluene, or diethyl ether), typicallyunder mixing or stirring conditions, and allowed to react at aconvenient temperature (e.g., room temperature or below, refluxing orabove, or an intermediate temperature) for a length of time to form asufficient amount of the desired product. Preferably, the components arecombined under an inert atmosphere (e.g., argon), typically in thesubstantial absence of water.

The metal (M) source can be selected from the group consisting of aGroup II metal source, a Group III metal source, a Lanthanide metalsource, and combinations thereof. A wide variety of suitable metalsources would be apparent to one of skill. Such metal sources canoptionally include at least one neutral ligand Y as defined hereinabove. Exemplary metal sources include, for example, a M(II) halide(i.e., a M(II) compound having at least one halide ligand), a M(II)pseudohalide (i.e., a M(II) compound having at least one pseudohalideligand), a M(II) amide (i.e., a M(II) compound having at least one amideligand, e.g., a M(II) bis(hexamethyldisilazane) and/or a M(II)bis(hexamethyldisilazane)-bis(tetrahydrofuran)), a M(0) for use in ametal exchange reaction with a β-diketiminate metal complex (e.g., a tincomplex), or combinations thereof.

In one embodiment, each R¹, R², R³, R⁴, and R⁵ is independently hydrogenor an aliphatic group (e.g., an alkyl group or, in certain embodiments,an alkyl moiety) having 1 to 5 carbon atoms, with the proviso that atleast one of R², R³, and R⁴ is a moiety selected from the groupconsisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl,n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl,isopentyl, tert-pentyl, and neopentyl.

In another embodiment, each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group (e.g., an alkyl group or, in certainembodiments, an alkyl moiety) having 1 to 5 carbon atoms, with theproviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl.

The method provides a metal-containing compound of the formula (FormulaI):

wherein M, L, Y, R¹, R², R³, R⁴, and R⁵ are as defined above, nrepresents the valence state of the metal, z is from 0 to 10, and x isfrom 1 to n.

Sources for β-diketiminate ligands having at least one substituenthaving greater degrees of freedom than the corresponding substituent incertain known metal-containing compounds can be made, for example, usingcondensation reactions. For example, exemplary β-diketiminate ligandsources having at least one substituent having greater degrees offreedom than the corresponding substituent in certain knownmetal-containing compounds can be made by a method including combiningan amine of the formula R¹NH₂ with a compound of the formula (FormulaIV):

or a tautomer thereof,in the presence of an agent capable of activating the carbonyl group forreaction with the amine, under conditions sufficient to provide a ligandsource of the formula (Formula III):

or a tautomer thereof.Preferably, the components are combined in an organic solvent (e.g.,heptane, toluene, or diethyl ether), typically under mixing or stirringconditions, and allowed to react at a convenient temperature (e.g., roomtemperature or below, refluxing or above, or an intermediatetemperature) for a length of time to form a sufficient amount of thedesired product. Preferably, the components are combined under an inertatmosphere (e.g., argon), typically in the substantial absence of water.

In one embodiment, each R¹, R², R³, R⁴, and R⁵ is independently hydrogenor an aliphatic group (e.g., an alkyl group or, in certain embodiments,an alkyl moiety) having 1 to 5 carbon atoms, with the proviso that atleast one of R², R³, and R⁴ is a moiety selected from the groupconsisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl,n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl,isopentyl, tert-pentyl, and neopentyl.

In another embodiment, each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group (e.g., an alkyl group or, in certainembodiments, an alkyl moiety) having 1 to 5 carbon atoms, with theproviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl.

Tautomers of compounds of Formula III and Formula IV include isomers inwhich a hydrogen atom is bonded to another atom. Typically, tautomerscan be in equilibrium with one another.

Specifically, the present invention contemplates tautomers of FormulaIII including, for example,

Similarly, the present invention contemplates tautomers of Formula IVincluding, for example,

Suitable activating agents capable of activating a carbonyl group forreaction with an amine are well known to those of skill in the art andinclude, for example, alkylating agents and Lewis acids (e.g., TiCl₄).Exemplary alkylating agents include triethyloxonium tetrafluoroborate,dimethyl sulfate, nitrosoureas, mustard gases (e.g.,1,1-thiobis(2-chloroethane)), and combinations thereof.

Additional metal-containing compounds including at least oneβ-diketiminate ligand having at least one substituent having greaterdegrees of freedom than the corresponding substituent in certain knownmetal-containing compounds can be made, for example, by ligand exchangereactions between a metal-containing compound including at least oneβ-diketiminate ligand having at least one substituent having greaterdegrees of freedom than the corresponding substituent in certain knownmetal-containing compounds, and a metal-containing compound including atleast one different β-diketiminate ligand. Such an exemplary methodincludes combining components including a compound of the formula(Formula I):

and a compound of the formula (Formula V):

under conditions sufficient to form the metal-containing compound.

Each M is a Group 2 metal, a Group 3 metal, a Lanthanide, or acombination thereof; each L is independently an anionic ligand; each Yis independently a neutral ligand; n represents the valence state of themetal; z is from 0 to 10; and x is from 1 to n.

In one embodiment, each R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ isindependently hydrogen or an aliphatic group (e.g., an alkyl group or,in certain embodiments, an alkyl moiety) having 1 to 5 carbon atoms,with the proviso that at least one of R², R³, R⁴, R⁷, R⁸, and R⁹ is amoiety selected from the group consisting of ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, isobutyl, n-pentyl, 2-pentyl, 3-pentyl,2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, tert-pentyl, andneopentyl; and the β-diketiminate ligands shown in Formula I and FormulaV have different structures.

In another embodiment, each R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰is independently hydrogen or an aliphatic group (e.g., an alkyl groupor, in certain embodiments, an alkyl moiety) having 1 to 5 carbon atoms,with the proviso that at least one of R¹, R⁵, R⁶, and R¹⁰ is a moietyselected from the group consisting of n-propyl, n-butyl, sec-butyl,isobutyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl,3-methyl-2-butyl, isopentyl, and tert-pentyl; and the β-diketiminateligands shown in Formula I and Formula V have different structures.

The method can provide a metal-containing compound of the formula(Formula II):

wherein M, L, Y, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, n, and z areas defined above.Other Metal-Containing Compounds

Precursor compositions that include a metal-containing compound thatincludes at least one β-diketiminate ligand can be useful for depositingmetal-containing layers using vapor deposition methods. In addition,such vapor deposition methods can also include precursor compositionsthat include one or more different metal-containing compounds. Suchprecursor compositions can be deposited/chemisorbed, for example in anALD process discussed more fully below, substantially simultaneouslywith or sequentially to, the precursor compositions includingmetal-containing compounds with at least one β-diketiminate ligand. Themetals of such different metal-containing compounds can include, forexample, Ti, Ta, Bi, Hf, Zr, Pb, Nb, Mg, Al, and combinations thereof.Suitable different metal-containing compounds include, for example,tetrakis titanium isopropoxide, titanium tetrachloride,trichlorotitanium dialkylamides, tetrakis titanium dialkylamides,tetrakis hafnium dialkylamides, trimethyl aluminum, zirconium (IV)chloride, pentakis tantalum ethoxide, and combinations thereof.

Vapor Deposition Methods

The metal-containing layer can be deposited, for example, on a substrate(e.g., a semiconductor substrate or substrate assembly). “Semiconductorsubstrate” or “substrate assembly” as used herein refer to asemiconductor substrate such as a base semiconductor layer or asemiconductor substrate having one or more layers, structures, orregions formed thereon. A base semiconductor layer is typically thelowest layer of silicon material on a wafer or a silicon layer depositedon another material, such as silicon on sapphire. When reference is madeto a substrate assembly, various process steps may have been previouslyused to form or define regions, junctions, various structures orfeatures, and openings such as transistors, active areas, diffusions,implanted regions, vias, contact openings, high aspect ratio openings,capacitor plates, barriers for capacitors, etc.

“Layer,” as used herein, refers to any layer that can be formed on asubstrate from one or more precursors and/or reactants according to thedeposition process described herein. The term “layer” is meant toinclude layers specific to the semiconductor industry, such as, butclearly not limited to a barrier layer, dielectric layer (i.e., a layerhaving a high dielectric constant), and conductive layer. The term“layer” is synonymous with the term “film” frequently used in thesemiconductor industry. The term “layer” is also meant to include layersfound in technology outside of semiconductor technology, such ascoatings on glass. For example, such layers can be formed directly onfibers, wires, etc., which are substrates other than semiconductorsubstrates. Further, the layers can be formed directly on the lowestsemiconductor surface of the substrate, or they can be formed on any ofa variety of layers (e.g., surfaces) as in, for example, a patternedwafer.

The layers or films formed may be in the form of metal-containing films,such as reduced metals, metal silicates, metal oxides, metal nitrides,etc, as well as combinations thereof. For example, a metal oxide layermay include a single metal, the metal oxide layer may include two ormore different metals (i.e., it is a mixed metal oxide), or a metaloxide layer may optionally be doped with other metals.

If the metal oxide layer includes two or more different metals, themetal oxide layer can be in the form of alloys, solid solutions, ornanolaminates. Preferably, these have dielectric properties. The metaloxide layer (particularly if it is a dielectric layer) preferablyincludes one or more of BaTiO₃, SrTiO₃, CaTiO₃, (Ba,Sr)TiO₃, SrTa₂O₆,SrBi₂Ta₂O₉ (SBT), SrHfO₃, SrZrO₃, BaHfO₃, BaZrO₃, (Pb,Ba)Nb₂O₆,(Sr,Ba)Nb₂O₆, Pb[(Sc,Nb)_(0.575)Ti_(0.425)]O₃ (PSNT), La₂O₃, Y₂O₃,LaAlO₃, YAlO₃, Pr₂O₃, Ba(Li,Nb)_(1/4)O₃—PbTiO₃, andBa(0.6)Sr(0.4)TiO₃—MgO. Surprisingly, the metal oxide layer formedaccording to the present invention is essentially free of carbon.Preferably metal-oxide layers formed by the systems and methods of thepresent invention are essentially free of carbon, hydrogen, halides,phosphorus, sulfur, nitrogen or compounds thereof. As used herein,“essentially free” is defined to mean that the metal-containing layermay include a small amount of the above impurities. For example, formetal-oxide layers, “essentially free” means that the above impuritiesare present in an amount of less than 1 atomic percent, such that theyhave a minor effect on the chemical properties, mechanical properties,physical form (e.g., crystallinity), or electrical properties of thefilm.

Various metal-containing compounds can be used in various combinations,optionally with one or more organic solvents (particularly for CVDprocesses), to form a precursor composition. Advantageously, some of themetal-containing compounds disclosed herein can be used in ALD withoutadding solvents. “Precursor” and “precursor composition” as used herein,refer to a composition usable for forming, either alone or with otherprecursor compositions (or reactants), a layer on a substrate assemblyin a deposition process. Further, one skilled in the art will recognizethat the type and amount of precursor used will depend on the content ofa layer which is ultimately to be formed using a vapor depositionprocess. The preferred precursor compositions of the present inventionare preferably liquid at the vaporization temperature and, morepreferably, are preferably liquid at room temperature.

The precursor compositions may be liquids or solids at room temperature(preferably, they are liquids at the vaporization temperature).Typically, they are liquids sufficiently volatile to be employed usingknown vapor deposition techniques. However, as solids they may also besufficiently volatile that they can be vaporized or sublimed from thesolid state using known vapor deposition techniques. If they are lessvolatile solids, they are preferably sufficiently soluble in an organicsolvent or have melting points below their decomposition temperaturessuch that they can be used in flash vaporization, bubbling, microdropletformation techniques, etc.

Herein, vaporized metal-containing compounds may be used either alone oroptionally with vaporized molecules of other metal-containing compoundsor optionally with vaporized solvent molecules or inert gas molecules,if used. As used herein, “liquid” refers to a solution or a neat liquid(a liquid at room temperature or a solid at room temperature that meltsat an elevated temperature). As used herein, “solution” does not requirecomplete solubility of the solid but may allow for some undissolvedsolid, as long as there is a sufficient amount of the solid delivered bythe organic solvent into the vapor phase for chemical vapor depositionprocessing. If solvent dilution is used in deposition, the total molarconcentration of solvent vapor generated may also be considered as ainert carrier gas.

“Inert gas” or “non-reactive gas,” as used herein, is any gas that isgenerally unreactive with the components it comes in contact with. Forexample, inert gases are typically selected from a group includingnitrogen, argon, helium, neon, krypton, xenon, any other non-reactivegas, and mixtures thereof. Such inert gases are generally used in one ormore purging processes described according to the present invention, andin some embodiments may also be used to assist in precursor vaportransport.

Solvents that are suitable for certain embodiments of the presentinvention may be one or more of the following: aliphatic hydrocarbons orunsaturated hydrocarbons (C3-C20, and preferably C5-C10, cyclic,branched, or linear), aromatic hydrocarbons (C5-C20, and preferablyC5-C10), halogenated hydrocarbons, silylated hydrocarbons such asalkylsilanes, alkylsilicates, ethers, polyethers, thioethers, esters,lactones, nitrites, silicone oils, or compounds containing combinationsof any of the above or mixtures of one or more of the above. Thecompounds are also generally compatible with each other, so thatmixtures of variable quantities of the metal-containing compounds willnot interact to significantly change their physical properties.

The precursor compositions of the present invention can, optionally, bevaporized and deposited/chemisorbed substantially simultaneously with,and in the presence of one or more reaction gases. Alternatively, themetal-containing layers may be formed by alternately introducing theprecursor composition and the reaction gas(es) during each depositioncycle. Such reaction gases may typically include oxygen, water vapor,ozone, nitrogen oxides, sulfur oxides, hydrogen, hydrogen sulfide,hydrogen selenide, hydrogen telluride, hydrogen peroxide, ammonia,organic amines, hydrazines (e.g., hydrazine, methylhydrazine,symmetrical and unsymmetrical dimethylhydrazines), silanes, disilanesand higher silanes, diborane, plasma, air, borazene (nitrogen source),carbon monoxide (reductant), alcohols, and any combination of thesegases. For example, oxygen-containing sources are typically used for thedeposition of metal-oxide layers. Preferable optional reaction gasesused in the formation of metal-oxide layers include oxidizing gases(e.g. oxygen, ozone, and nitric oxide).

Suitable substrate materials of the present invention include conductivematerials, semiconductive materials, conductive metal-nitrides,conductive metals, conductive metal oxides, etc. The substrate on whichthe metal-containing layer is formed is preferably a semiconductorsubstrate or substrate assembly. A wide variety of semiconductormaterials are contemplated, such as for example, borophosphosilicateglass (BPSG), silicon such as, e.g., conductively doped polysilicon,monocrystalline silicon, etc. (for this invention, appropriate forms ofsilicon are simply referred to as “silicon”), for example in the form ofa silicon wafer, tetraethylorthosilicate (TEOS) oxide, spin on glass(i.e., a thin layer of SiO₂, optionally doped, deposited by a spin onprocess), TiN, TaN, W, Ru, Al, Cu, noble metals, etc. A substrateassembly may also contain a layer that includes platinum, iridium,iridium oxide, rhodium, ruthenium, ruthenium oxide, strontium ruthenate,lanthanum nickelate, titanium nitride, tantalum nitride,tantalum-silicon-nitride, silicon dioxide, aluminum, gallium arsenide,glass, etc., and other existing or to-be-developed materials used insemiconductor constructions, such as dynamic random access memory (DRAM)devices, static random access memory (SRAM) devices, and ferroelectricmemory (FERAM) devices, for example.

For substrates including semiconductor substrates or substrateassemblies, the layers can be formed directly on the lowestsemiconductor surface of the substrate, or they can be formed on any ofa variety of the layers (i.e., surfaces) as in a patterned wafer, forexample.

Substrates other than semiconductor substrates or substrate assembliescan also be used in methods of the present invention. Any substrate thatmay advantageously form a metal-containing layer thereon, such as ametal oxide layer, may be used, such substrates including, for example,fibers, wires, etc.

A preferred deposition process for the present invention is a vapordeposition process. Vapor deposition processes are generally favored inthe semiconductor industry due to the process capability to quicklyprovide highly conformal layers even within deep contacts and otheropenings.

The precursor compositions can be vaporized in the presence of an inertcarrier gas if desired. Additionally, an inert carrier gas can be usedin purging steps in an ALD process (discussed below). The inert carriergas is typically one or more of nitrogen, helium, argon, etc. In thecontext of the present invention, an inert carrier gas is one that doesnot interfere with the formation of the metal-containing layer. Whetherdone in the presence of a inert carrier gas or not, the vaporization ispreferably done in the absence of oxygen to avoid oxygen contaminationof the layer (e.g., oxidation of silicon to form silicon dioxide oroxidation of precursor in the vapor phase prior to entry into thedeposition chamber).

Chemical vapor deposition (CVD) and atomic layer deposition (ALD) aretwo vapor deposition processes often employed to form thin, continuous,uniform, metal-containing layers onto semiconductor substrates. Usingeither vapor deposition process, typically one or more precursorcompositions are vaporized in a deposition chamber and optionallycombined with one or more reaction gases and directed to and/orcontacted with the substrate to form a metal-containing layer on thesubstrate. It will be readily apparent to one skilled in the art thatthe vapor deposition process may be enhanced by employing variousrelated techniques such as plasma assistance, photo assistance, laserassistance, as well as other techniques.

Chemical vapor deposition (CVD) has been extensively used for thepreparation of metal-containing layers, such as dielectric layers, insemiconductor processing because of its ability to provide conformal andhigh quality dielectric layers at relatively fast processing times.Typically, the desired precursor compositions are vaporized and thenintroduced into a deposition chamber containing a heated substrate withoptional reaction gases and/or inert carriers gases in a singledeposition cycle. In a typical CVD process, vaporized precursors arecontacted with reaction gas(es) at the substrate surface to form a layer(e.g., dielectric layer). The single deposition cycle is allowed tocontinue until the desired thickness of the layer is achieved.

Typical CVD processes generally employ precursor compositions invaporization chambers that are separated from the process chamberwherein the deposition surface or wafer is located. For example, liquidprecursor compositions are typically placed in bubblers and heated to atemperature at which they vaporize, and the vaporized liquid precursorcomposition is then transported by an inert carrier gas passing over thebubbler or through the liquid precursor composition. The vapors are thenswept through a gas line to the deposition chamber for depositing alayer on substrate surface(s) therein. Many techniques have beendeveloped to precisely control this process. For example, the amount ofprecursor composition transported to the deposition chamber can beprecisely controlled by the temperature of the reservoir containing theprecursor composition and by the flow of an inert carrier gas bubbledthrough or passed over the reservoir.

A typical CVD process may be carried out in a chemical vapor depositionreactor, such as a deposition chamber available under the tradedesignation of 7000 from Genus, Inc. (Sunnyvale, Calif.), a depositionchamber available under the trade designation of 5000 from AppliedMaterials. Inc. (Santa Clara, Calif.), or a deposition chamber availableunder the trade designation of Prism from Novelus, Inc. (San Jose,Calif.). However, any deposition chamber suitable for performing CVD maybe used.

Several modifications of the CVD process and chambers are possible, forexample, using atmospheric pressure chemical vapor deposition, lowpressure chemical vapor deposition (LPCVD), plasma enhanced chemicalvapor deposition (PECVD), hot wall or cold wall reactors or any otherchemical vapor deposition technique. Furthermore, pulsed CVD can beused, which is similar to ALD (discussed in greater detail below) butdoes not rigorously avoid intermixing of precursor and reactant gasstreams. Also, for pulsed CVD, the deposition thickness is dependent onthe exposure time, as opposed to ALD, which is self-limiting (discussedin more detail below).

Alternatively, and preferably, the vapor deposition process employed inthe methods of the present invention is a multi-cycle atomic layerdeposition (ALD) process. Such a process is advantageous, in particularadvantageous over a CVD process, in that it provides for improvedcontrol of atomic-level thickness and uniformity to the deposited layer(e.g., dielectric layer) by providing a plurality of deposition cycles.The self-limiting nature of ALD provides a method of depositing a filmon a wide variety of reactive surfaces including, for example, surfaceswith irregular topographies, with better step coverage than is availablewith CVD or other “line of sight” deposition methods (e.g., evaporationand physical vapor deposition, i.e., PVD or sputtering). Further, ALDprocesses typically expose the metal-containing compounds to lowervolatilization and reaction temperatures, which tends to decreasedegradation of the precursor as compared to, for example, typical CVDprocesses. See, for example, U.S. Pat. No. 7,416,994 (Quick).

Generally, in an ALD process each reactant is pulsed sequentially onto asuitable substrate, typically at deposition temperatures of at least 25°C., preferably at least 150° C., and more preferably at least 200° C.Typical ALD deposition temperatures are no greater than 400° C.preferably no greater than 350° C., and even more preferably no greaterthan 250° C. These temperatures are generally lower than those presentlyused in CVD processes, which typically include deposition temperaturesat the substrate surface of at least 150° C. preferably at least 200°C., and more preferably at least 250° C. Typical CVD depositiontemperatures are no greater than 600° C., preferably no greater than500° C., and even more preferably no greater than 400° C.

Under such conditions the film growth by ALD is typically self-limiting(i.e., when the reactive sites on a surface are used up in an ALDprocess, the deposition generally stops), insuring not only excellentconformality but also good large area uniformity plus simple andaccurate composition and thickness control. Due to alternate dosing ofthe precursor compositions and/or reaction gases, detrimentalvapor-phase reactions are inherently eliminated, in contrast to the CVDprocess that is carried out by continuous co-reaction of the precursorsand/or reaction gases. (See Vehkamäki et al., “Growth of SrTiO₃ andBaTiO₃ Thin Films by Atomic Layer Deposition,” Electrochemical andSolid-State Letters, 2(10):504-506 (1999)).

A typical ALD process includes exposing a substrate (which mayoptionally be pretreated with, for example, water and/or ozone) to afirst chemical to accomplish chemisorption of the species onto thesubstrate. The term “chemisorption” as used herein refers to thechemical adsorption of vaporized reactive metal-containing compounds onthe surface of a substrate. The adsorbed species are typicallyirreversibly bound to the substrate surface as a result of relativelystrong binding forces characterized by high adsorption energies(e.g., >30 kcal/mol), comparable in strength to ordinary chemical bonds.The chemisorbed species typically form a monolayer on the substratesurface. (See “The Condensed Chemical Dictionary”, 10th edition, revisedby G. G. Hawley, published by Van Nostrand Reinhold Co. New York, 225(1981)). The technique of ALD is based on the principle of the formationof a saturated monolayer of reactive precursor molecules bychemisorption. In ALD one or more appropriate precursor compositions orreaction gases are alternately introduced (e.g., pulsed) into adeposition chamber and chemisorbed onto the surfaces of a substrate.Each sequential introduction of a reactive compound (e.g., one or moreprecursor compositions and one or more reaction gases) is typicallyseparated by an inert carrier gas purge. Each precursor compositionco-reaction adds a new atomic layer to previously deposited layers toform a cumulative solid layer. The cycle is repeated to gradually formthe desired layer thickness. It should be understood that ALD canalternately utilize one precursor composition, which is chemisorbed, andone reaction gas, which reacts with the chemisorbed species.

Practically, chemisorption might not occur on all portions of thedeposition surface (e.g., previously deposited ALD material).Nevertheless, such imperfect monolayer is still considered a monolayerin the context of the present invention. In many applications, merely asubstantially saturated monolayer may be suitable. A substantiallysaturated monolayer is one that will still yield a deposited monolayeror less of material exhibiting the desired quality and/or properties.

A typical ALD process includes exposing an initial substrate to a firstchemical species A (e.g., a metal-containing compound as describedherein) to accomplish chemisorption of the species onto the substrate.Species A can react either with the substrate surface or with Species B(described below) but not with itself. Typically in chemisorption, oneor more of the ligands of Species A is displaced by reactive groups onthe substrate surface. Theoretically, the chemisorption forms amonolayer that is uniformly one atom or molecule thick on the entireexposed initial substrate, the monolayer being composed of Species A,less any displaced ligands. In other words, a saturated monolayer issubstantially formed on the substrate surface. Practically,chemisorption may not occur on all portions of the substrate.Nevertheless, such a partial monolayer is still understood to be amonolayer in the context of the present invention. In many applications,merely a substantially saturated monolayer may be suitable. In oneaspect, a substantially saturated monolayer is one that will still yielda deposited monolayer or less of material exhibiting the desired qualityand/or properties. In another aspect, a substantially saturatedmonolayer is one that is self-limited to further reaction withprecursor.

The first species (e.g., substantially all non-chemisorbed molecules ofSpecies A) as well as displaced ligands are purged from over thesubstrate and a second chemical species, Species B (e.g., a differentmetal-containing compound or reactant gas) is provided to react with themonolayer of Species A. Species B typically displaces the remainingligands from the Species A monolayer and thereby is chemisorbed andforms a second monolayer. This second monolayer displays a surface whichis reactive only to Species A. Non-chemisorbed Species B, as well asdisplaced ligands and other byproducts of the reaction are then purgedand the steps are repeated with exposure of the Species B monolayer tovaporized Species A. Optionally, the second species can react with thefirst species, but not chemisorb additional material thereto. That is,the second species can cleave some portion of the chemisorbed firstspecies, altering such monolayer without forming another monolayerthereon, but leaving reactive sites available for formation ofsubsequent monolayers. In other ALD processes, a third species or moremay be successively chemisorbed (or reacted) and purged just asdescribed for the first and second species, with the understanding thateach introduced species reacts with the monolayer produced immediatelyprior to its introduction. Optionally, the second species (or third orsubsequent) can include at least one reaction gas if desired.

Thus, the use of ALD provides the ability to improve the control ofthickness, composition, and uniformity of metal-containing layers on asubstrate. For example, depositing thin layers of metal-containingcompound in a plurality of cycles provides a more accurate control ofultimate film thickness. This is particularly advantageous when theprecursor composition is directed to the substrate and allowed tochemisorb thereon, preferably further including at least one reactiongas that reacts with the chemisorbed species on the substrate, and evenmore preferably wherein this cycle is repeated at least once.

Purging of excess vapor of each species followingdeposition/chemisorption onto a substrate may involve a variety oftechniques including, but not limited to, contacting the substrateand/or monolayer with an inert carrier gas and/or lowering pressure tobelow the deposition pressure to reduce the concentration of a speciescontacting the substrate and/or chemisorbed species. Examples of carriergases, as discussed above, may include N₂, Ar, He, etc. Additionally,purging may instead include contacting the substrate and/or monolayerwith any substance that allows chemisorption by-products to desorb andreduces the concentration of a contacting species preparatory tointroducing another species. The contacting species may be reduced tosome suitable concentration or partial pressure known to those skilledin the art based on the specifications for the product of a particulardeposition process.

ALD is often described as a self-limiting process, in that a finitenumber of sites exist on a substrate to which the first species may formchemical bonds. The second species might only react with the surfacecreated from the chemisorption of the first species and thus, may alsobe self-limiting. Once all of the finite number of sites on a substrateare bonded with a first species, the first species will not bond toother of the first species already bonded with the substrate. However,process conditions can be varied in ALD to promote such bonding andrender ALD not self-limiting, e.g., more like pulsed CVD. Accordingly,ALD may also encompass a species forming other than one monolayer at atime by stacking of a species, forming a layer more than one atom ormolecule thick.

The described method indicates the “substantial absence” of the secondprecursor (i.e., second species) during chemisorption of the firstprecursor since insignificant amounts of the second precursor might bepresent. According to the knowledge and the preferences of those withordinary skill in the art, a determination can be made as to thetolerable amount of second precursor and process conditions selected toachieve the substantial absence of the second precursor.

Thus, during the ALD process, numerous consecutive deposition cycles areconducted in the deposition chamber, each cycle depositing a very thinmetal-containing layer (usually less than one monolayer such that thegrowth rate on average is 0.2 to 3.0 Angstroms per cycle), until a layerof the desired thickness is built up on the substrate of interest. Thelayer deposition is accomplished by alternately introducing (i.e., bypulsing) precursor composition(s) into the deposition chamber containinga substrate, chemisorbing the precursor composition(s) as a monolayeronto the substrate surfaces, purging the deposition chamber, thenintroducing to the chemisorbed precursor composition(s) reaction gasesand/or other precursor composition(s) in a plurality of depositioncycles until the desired thickness of the metal-containing layer isachieved. Preferred thicknesses of the metal-containing layers of thepresent invention are at least 1 angstrom (Å), more preferably at least5 Å, and more preferably at least 10 Å. Additionally, preferred filmthicknesses are typically no greater than 500 Å, more preferably nogreater than 400 Å, and more preferably no greater than 300 Å.

The pulse duration of precursor composition(s) and inert carrier gas(es)is generally of a duration sufficient to saturate the substrate surface.Typically, the pulse duration is at least 0.1, preferably at least 0.2second, and more preferably at least 0.5 second. Preferred pulsedurations are generally no greater than 5 seconds, and preferably nogreater than 3 seconds.

In comparison to the predominantly thermally driven CVD, ALD ispredominantly chemically driven. Thus, ALD may advantageously beconducted at much lower temperatures than CVD. During the ALD process,the substrate temperature may be maintained at a temperaturesufficiently low to maintain intact bonds between the chemisorbedprecursor composition(s) and the underlying substrate surface and toprevent decomposition of the precursor composition(s). The temperature,on the other hand, must be sufficiently high to avoid condensation ofthe precursor composition(s). Typically the substrate is kept at atemperature of at least 25° C., preferably at least 150° C., and morepreferably at least 200° C. Typically the substrate is kept at atemperature of no greater than 400° C., preferably no greater than 300°C., and more preferably no greater than 250° C. which, as discussedabove, is generally lower than temperatures presently used in typicalCVD processes. Thus, the first species or precursor composition ischemisorbed at this temperature. Surface reaction of the second speciesor precursor composition can occur at substantially the same temperatureas chemisorption of the first precursor or, optionally but lesspreferably, at a substantially different temperature. Clearly, somesmall variation in temperatures as judged by those of ordinary skill,can occur but still be considered substantially the same temperature byproviding a reaction rate statistically the same as would occur at thetemperature of the first precursor chemisorption. Alternatively,chemisorption and subsequent reactions could instead occur atsubstantially exactly the same temperature.

For a typical vapor deposition process, the pressure inside thedeposition chamber is at least 10⁻⁸ torr (1.3×10⁻⁶ Pa), preferably atleast 10⁻⁷ torr (1.3×10⁻⁵ Pa), and more preferably at least 10⁻⁶ torr(1.3×10⁻⁴ Pa). Further, deposition pressures are typically no greaterthan 10 torr (1.3×10³ Pa), preferably no greater than 1 torr (1.3×10²Pa), and more preferably no greater than 10⁻¹ torr (13 Pa). Typically,the deposition chamber is purged with an inert carrier gas after thevaporized precursor composition(s) have been introduced into the chamberand/or reacted for each cycle. The inert carrier gas/gases can also beintroduced with the vaporized precursor composition(s) during eachcycle.

The reactivity of a precursor composition can significantly influencethe process parameters in ALD. Under typical CVD process conditions, ahighly reactive compound may react in the gas phase generatingparticulates, depositing prematurely on undesired surfaces, producingpoor films, and/or yielding poor step coverage or otherwise yieldingnon-uniform deposition. For at least such reason, a highly reactivecompound might be considered not suitable for CVD. However, somecompounds not suitable for CVD are superior ALD precursors. For example,if the first precursor is gas phase reactive with the second precursor,such a combination of compounds might not be suitable for CVD, althoughthey could be used in ALD. In the CVD context, concern might also existregarding sticking coefficients and surface mobility, as known to thoseskilled in the art, when using highly gas-phase reactive precursors,however, little or no such concern would exist in the ALD context.

After layer formation on the substrate, an annealing process may beoptionally performed in situ in the deposition chamber in a reducing,inert, plasma, or oxidizing atmosphere. Preferably, the annealingtemperature is at least 400° C., more preferably at least 600° C. Theannealing temperature is preferably no greater than 1000° C., morepreferably no greater than 750° C. and even more preferably no greaterthan 700° C.

The annealing operation is preferably performed for a time period of atleast 0.5 minute, more preferably for a time period of at least 1minute. Additionally, the annealing operation is preferably performedfor a time period of no greater than 60 minutes, and more preferably fora time period of no greater than 10 minutes.

One skilled in the art will recognize that such temperatures and timeperiods may vary. For example, furnace anneals and rapid thermalannealing may be used, and further, such anneals may be performed in oneor more annealing steps.

As stated above, the use of the compounds and methods of forming filmsof the present invention are beneficial for a wide variety of thin filmapplications in semiconductor structures, particularly those using highdielectric materials. For example, such applications include gatedielectrics and capacitors such as planar cells, trench cells (e.g.,double sidewall trench capacitors), stacked cells (e.g., crown, V-cell,delta cell, multi-fingered, or cylindrical container stackedcapacitors), as well as field effect transistor devices.

A system that can be used to perform vapor deposition processes(chemical vapor deposition or atomic layer deposition) of the presentinvention is shown in FIG. 1. The system includes an enclosed vapordeposition chamber 10, in which a vacuum may be created using turbo pump12 and backing pump 14. One or more substrates 16 (e.g., semiconductorsubstrates or substrate assemblies) are positioned in chamber 10. Aconstant nominal temperature is established for substrate 16, which canvary depending on the process used. Substrate 16 may be heated, forexample, by an electrical resistance heater 18 on which substrate 16 ismounted. Other known methods of heating the substrate may also beutilized.

In this process, precursor compositions as described herein, 60 and/or61, are stored in vessels 62. The precursor composition(s) are vaporizedand separately fed along lines 64 and 66 to the deposition chamber 10using, for example, an inert carrier gas 68. A reaction gas 70 may besupplied along line 72 as needed. Also, a purge gas 74, which is oftenthe same as the inert carrier gas 68, may be supplied along line 76 asneeded. As shown, a series of valves 80-85 are opened and closed asrequired.

The following examples are offered to further illustrate variousspecific embodiments and techniques of the present invention. It shouldbe understood, however, that many variations and modificationsunderstood by those of ordinary skill in the art may be made whileremaining within the scope of the present invention. Therefore, thescope of the invention is not intended to be limited by the followingexample. Unless specified otherwise, all percentages shown in theexamples are percentages by weight.

EXAMPLES Example 1 Synthesis and Characterization of a Ligand Source ofFormula III, with R¹═R⁵=sec-butyl; R²═R⁴=methyl; and R³═H:N-sec-butyl-(4-sec-butylimino)-2-penten-2-amine

An oven-dry 1-L Schlenk flask fitted with addition funnel was chargedwith 101 mL of sec-butylamine and 200 mL dichloromethane. The additionfunnel was then charged with 103 mL of 2,4-pentanedione and 400 mLdichloromethane, which were then added dropwise to the solution in theSchlenk flask. The resulting solution was then stirred for 90 hours. Theaqueous phase formed during the reaction was then separated andextracted with 2×50 mL portions of diethyl ether. The combined organicfractions were dried over anhydrous sodium sulfate and concentrated on arotary evaporator. The concentrate was then distilled at 66° C., 0.7Torr (93 Pa); the distillate was a clear colorless liquid. 108.4 g werecollected for 70% yield. Gas chromatographic/mass spectrometric (GC/MS)analysis of the distillate indicated a compound with an apparent purityof 99.9% having a mass spectrum consistent withN-sec-butyl-4-amino-3-penten-2-one.

An oven-dry 500-mL Schlenk flask was charged with 38.0 g oftriehyloxonium tetrafluoroborate (0.2 mol) under argon atmosphere andfitted with an addition funnel. 200 mL of dichloromethane was added toform a clear colorless solution. A 60 mL portion of dichloromethane and31.05 grams of N-sec-butyl-4-amino-3-penten-2-one (0.2 mol) were chargedinto the addition funnel and this solution was added dropwise to thesolution in the Schlenk flask, and the resulting solution was thenstirred for 30 minutes. A solution of 20.2 mL sec-butyl amine (0.2 mol)and 30 mL dichloromethane was charged into the addition funnel and addedto the reaction solution, which was then stirred overnight. Volatileswere then removed in vacuo and the resulting yellow oily solid waswashed with 60 mL aliquot of cold ethyl acetate while the flask wasplaced in an ice-bath. No solid precipitate was observed due to thiswash; rather part of the crude product appeared to dissolve. Afterdecanting off the ethyl acetate wash, a second 60 mL ethyl acetate washwas attempted with identical results. Combined washes and crude productwere added to a mixture of 500 mL benzene and 500 mL water containing8.0 g sodium hydroxide (0.2 mol). The mixture was stirred for threeminutes and then the organic phase was separated. The aqueous phase wasextracted four times, each with 100 mL diethyl ether portions. All theorganic phases were combined, dried over sodium sulfate and concentratedon a rotary evaporator. The crude product was then distilled through a20 cm glass-bead packed column and short path still head. The desiredproduct was collected in ≧99% pure form at 60-63° C., 80 mTorr (10 Pa)pressure. The apparent purity was determined by GC/MS, where the onlyimpurity observed was N-sec-butyl-4-amino-3-penten-2-one.

Example 2 Synthesis and Characterization of a Metal-Containing Compoundof Formula I, with M=Sr (n=2); R¹═R=sec-butyl; R²═R⁴=methyl; R³═H; x=2;and z=0: Strontiumbis(N-sec-butyl-(4-sec-butylimino)-2-penten-2-aminato)

In a dry box, a 500 mL Schlenk flask was charged with 7.765 g ofstrontium bis(hexamethyldisilazane) (19 mmol) and 50 mL toluene. Asecond Schlenk flask was charged with 8.000 g ofN-sec-butyl-(4-sec-butylimino)-2-penten-2-amine (38 mmol) and 50 mLtoluene. The ligand solution was added to the strontium solution,immediately producing an amber-colored reaction solution which wasstirred for 18 hours. Volatiles were then removed in vacuo. The crudeproduct, a brown liquid, was charged into a 50 mL round-bottom Schlenkflask fitted with short path still head and Schlenk receiver flask inthe dry box. The distillation apparatus was attached to a vacuum lineand evacuated further, which induced some solidification in the stillpot. At full vacuum, heating of the still pot was begun. A clear liquid(approximately 0.5 g) was collected at 60° C.; GC/MS confirmed thismaterial to be the ligand precursor. A second receiver flask wasattached and the product was distilled at 145-160° C. at full vacuum.The “cooling lines” to the still head were filled with 90° C. ethyleneglycol to prevent the condensing distillate from becoming too viscousand clogging the still path. The collected product formed a yellow,slightly oily solid upon cooling. 6.585 g were collected for 71.6%yield. Elemental analysis calculated for C₂₆H₅₀N₄Sr: Sr, 17.3%. Found16.6%. Melting point of distilled product was determined to be 44-48° C.

¹H and ¹³C nuclear magnetic resonance (NMR) results were consistent withthe presence of four diastereomeric forms of the compound (twoenantiomeric pairs and two meso forms). ¹H NMR (C₆D₆, δ): 4.190 (m, 2H,J=2.4, 2.4 Hz, β-C—H), 3.330 (m, 4H, J=6.3 Hz, N—CH(CH₃)(CH₂CH₃)), 1.873(d, 12H, J=2.4 Hz, α-C—CH₃), 1.506 (m, 8H, J=1.4, 6.4 Hz,N—CH(CH₃)(CH₂CH₃)), 1.253-1.220 (d, 4 sets overlapping, 6H, J=6.15-6.45Hz, N—CH(CH₃)(CH₂CH₃)), 1.188-1.162 (d, 4 sets overlapping, 6H,J=6.15-6.45 Hz, N—CH(CH₃)(CH₂CH₃)), 0.970-0.897 (d, 4 sets overlapping,12H, J=6.2 Hz, N—CH(CH₃)(CH₂CH₃)). ¹³C NMR (C₆D₆, δ): 161.294, 161.226(α-C—CH₃); 94.80, 86.96, 86.89, 86.70 (β-CH); 56.19, 56.00, 52.67, 52.58(N—CH(CH₃)(CH₂CH₃)); 33.61, 33.56, 32.13, 32.04 (N—CH(CH₃)(CH₂CH₃));23.86, 23.78, 223.67 (α-C—CH₃); 22.47, 22.39 (N—CH(CH₃)(CH₂CH₃)); 11.63,11.33, 10.81, 10.75 (N—CH(CH₃)(CH₂CH₃)).

As illustrated in FIG. 2, the metal-containing compound having theformula (Formula I) where R¹═R⁵=sec-butyl (3 degrees of freedom forsec-butyl as quantified, for example, in Table 1) has a lower meltingpoint (44-48° C.) compared to disclosed melting points for thecorresponding metal-containing compounds having the formula (Formula I)(see, El-Kaderi et al., Organometallics, 23:4995-5002 (2004)) whereR¹═R⁵=isopropyl (87-89° C.; 1 degree of freedom for isopropyl asquantified, for example, in Table 1); and where R¹═R⁵=tert-butyl(127-129° C.; 0 degrees of freedom for tert-butyl as quantified, forexample, in Table 1).

The complete disclosures of the patents, patent documents, andpublications cited herein are incorporated by reference in theirentirety as if each were individually incorporated. Variousmodifications and alterations to this invention will become apparent tothose skilled in the art without departing from the scope and spirit ofthis invention. It should be understood that this invention is notintended to be unduly limited by the illustrative embodiments andexamples set forth herein and that such examples and embodiments arepresented by way of example only with the scope of the inventionintended to be limited only by the claims set forth herein as follows.

1. A method of forming a metal-containing layer on a substrate, themethod comprising: providing a substrate; providing a vapor comprisingat least one compound of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an organic group with the proviso that at least one of the Rgroups is a fluorine-containing organic group; and contacting the vaporcomprising the at least one compound of Formula I with the substrate toform a metal-containing layer on at least one surface of the substrateusing a vapor deposition process.
 2. The method of claim 1 wherein eachR¹, R², R³, R⁴, and R⁵ is independently hydrogen or an organic grouphaving 1 to 10 carbon atoms.
 3. The method of claim 1 wherein at leastone L is selected from the group consisting of a halide, an alkoxidegroup, an amide group, a mercaptide group, cyanide, an alkyl group, anamidinate group, a guanidinate group, an isoureate group, a β-diketonategroup, a β-iminoketonate group, a β-diketiminate group, and combinationsthereof.
 4. The method of claim 3 wherein the at least one L is aβ-diketiminate group having a structure that is the same as that of theβ-diketiminate ligand shown in Formula I.
 5. The method of claim 3wherein the at least one L is a β-diketiminate group having a structurethat is different than that of the β-diketiminate ligand shown inFormula I.
 6. The method of claim 1 wherein at least one Y is selectedfrom the group consisting of a carbonyl, a nitrosyl, ammonia, an amine,nitrogen, a phosphine, an alcohol, water, tetrahydrofuran, andcombinations thereof.
 7. A method of manufacturing a semiconductorstructure, the method comprising: providing a semiconductor substrate orsubstrate assembly; providing a vapor comprising at least one compoundof the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an organic group with the proviso that at least one of the Rgroups is a fluorine-containing organic group; and directing the vaporcomprising the at least one compound of Formula I to the semiconductorsubstrate or substrate assembly to form a metal-containing layer on atleast one surface of the semiconductor substrate or substrate assemblyusing a vapor deposition process.
 8. The method of claim 7 furthercomprising providing a vapor comprising at least one metal-containingcompound different than Formula I, and directing the vapor comprisingthe at least one metal-containing compound different than Formula I tothe semiconductor substrate or substrate assembly.
 9. The method ofclaim 8 wherein the metal of the at least one metal-containing compounddifferent than Formula I is selected from the group consisting of Ti,Ta, Bi, Hf, Zr, Pb, Nb, Mg, Al, and combinations thereof.
 10. The methodof claim 7 further comprising providing at least one reaction gas. 11.The method of claim 7 wherein the vapor deposition process is a chemicalvapor deposition process.
 12. The method of claim 7 wherein the vapordeposition process is an atomic layer deposition process comprising aplurality of deposition cycles.
 13. A method of forming ametal-containing layer on a substrate, the method comprising: providinga substrate; providing a vapor comprising at least one compound of theformula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group having 1 to 5 carbon atoms, with theproviso that at least one of R², R³, and R⁴ is a moiety selected fromthe group consisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,isobutyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl,3-methyl-2-butyl, isopentyl, tert-pentyl, and neopentyl; and contactingthe vapor comprising the at least one compound of Formula I with thesubstrate to form a metal-containing layer on at least one surface ofthe substrate using a vapor deposition process.
 14. The method of claim13 wherein at least one of R², R³, and R⁴ is sec-butyl.
 15. A method ofmanufacturing a semiconductor structure, the method comprising:providing a semiconductor substrate or substrate assembly; providing avapor comprising at least one compound of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group having 1 to 5 carbon atoms, with theproviso that at least one of R², R³, and R⁴ is a moiety selected fromthe group consisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,isobutyl, n-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl,3-methyl-2-butyl, isopentyl, tert-pentyl, and neopentyl; and directingthe vapor comprising the at least one compound of Formula I to thesemiconductor substrate or substrate assembly to form a metal-containinglayer on at least one surface of the semiconductor substrate orsubstrate assembly using a vapor deposition process.
 16. The method ofclaim 15 further comprising providing a vapor comprising at least onemetal-containing compound different than Formula I, and directing thevapor comprising the at least one metal-containing compound differentthan Formula I to the semiconductor substrate or substrate assembly. 17.The method of claim 16 wherein the metal of the at least onemetal-containing compound different than Formula I is selected from thegroup consisting of Ti, Ta, Bi, Hf, Zr, Pb, Nb, Mg, Al, and combinationsthereof.
 18. The method of claim 15 further comprising providing atleast one reaction gas.
 19. The method of claim 15 wherein the vapordeposition process is a chemical vapor deposition process.
 20. Themethod of claim 15 wherein the vapor deposition process is an atomiclayer deposition process comprising a plurality of deposition cycles.21. A method of forming a metal-containing layer on a substrate, themethod comprising: providing a substrate; providing a vapor comprisingat least one compound of the formula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group having 1 to 5 carbon atoms, with theproviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl; and contacting the vapor comprising the at least onecompound of Formula I with the substrate to form a metal-containinglayer on at least one surface of the substrate using a vapor depositionprocess.
 22. The method of claim 21 wherein at least one of R¹ and R⁵ issec-butyl.
 23. A method manufacturing a semiconductor structure, themethod comprising: providing a semiconductor substrate or substrateassembly; providing a vapor comprising at least one compound of theformula (Formula I):

wherein: M is selected from the group consisting of a Group 2 metal, aGroup 3 metal, a Lanthanide, and combinations thereof; each L isindependently an anionic ligand; each Y is independently a neutralligand; n represents the valence state of the metal; z is from 0 to 10;x is from 1 to n; and each R¹, R², R³, R⁴, and R⁵ is independentlyhydrogen or an aliphatic group having 1 to 5 carbon atoms, with theproviso that at least one of R¹ and R⁵ is a moiety selected from thegroup consisting of n-propyl, n-butyl, sec-butyl, isobutyl, n-pentyl,2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-2-butyl, isopentyl, andtert-pentyl; and directing the vapor comprising the at least onecompound of Formula I to the semiconductor substrate or substrateassembly to form a metal-containing layer on at least one surface of thesemiconductor substrate or substrate assembly using a vapor depositionprocess.
 24. The method of claim 23 further comprising providing a vaporcomprising at least one metal-containing compound different than FormulaI, and directing the vapor comprising the at least one metal-containingcompound different than Formula I to the semiconductor substrate orsubstrate assembly.
 25. The method of claim 24 wherein the metal of theat least one metal-containing compound different than Formula I isselected from the group consisting of Ti, Ta, Bi, Hf, Zr, Pb, Nb, Mg,Al, and combinations thereof.
 26. The method of claim 23 furthercomprising providing at least one reaction gas.
 27. The method of claim23 wherein the vapor deposition process is a chemical vapor depositionprocess.
 28. The method of claim 23 wherein the vapor deposition processis an atomic layer deposition process comprising a plurality ofdeposition cycles.